This disclosure relates generally to the fabrication of semiconductor dice, such as vertical light emitting diode (VLED) dice, and to a method for fabricating semiconductor dice by separating a substrate from semiconductor structures using multiple laser pulses.
Semiconductor dice can include semiconductor structures made of different layers of compound semiconductor materials. For example, one type of semiconductor die, known as a vertical light emitting diode (VLED) die, includes a semiconductor structure in the form of an epitaxial stack comprised of a p-type confinement layer, an n-type confinement layer, and an active layer (multiple quantum well (MQW) layer) between the confinement layers configured to emit light. The semiconductor structure can be fabricated on a carrier substrate that is a component of a wafer assembly containing multiple semiconductor dice. During the fabrication process, the carrier substrate can be separated from the semiconductor structures and other components, such as electrodes, metallization layers and bases can be formed on the dice contained on the wafer assembly. The wafer assembly can then be singulated into the individual dice.
Separation of the carrier substrate from the semiconductor structures contained on the wafer assembly can be performed using a laser, an etching process, a grinding process or chemical mechanical planarization (CMP). One problem occurring during the separation process is that the semiconductor structures can be damaged by the forces applied to separate the carrier substrate. For example, cracking and peeling of the semiconductor structures can occur due to the energy applied by a laser, an etchant, a grinder or by a CMP apparatus used to separate the carrier substrate.
The present disclosure is directed to a method for fabricating semiconductor dice that minimizes damage to the semiconductor structures during the separation of a substrate from semiconductor structures.